Andretti had originally tried to enter the sport under their own name, but that initial bid was pushed back, before it became clear that the General Motors-backed Cadillac name would be the driving force behind a second successful bid.
Andretti currently race in multiple other series around the world, including IndyNXT, IndyCar and Formula E.
Former F1 racer Marcus Ericsson drives for the brand's IndyCar team, claiming one podium in 2024 and finishing 15th in the overall standings.
Ericsson raced in F1 between 2014 and 2018, with the Caterham and Sauber teams, but struggled to be a regular points-scoring driver.
The Swedish driver has competed in IndyCar ever since, for a variety of different teams, but is now set to be given a new role in F1.
Ericsson revealed that he is set to fly to the UK to work on Cadillac's simulator, where they will decide which direction to take their F1 car in for 2026, as well as making decisions around future IndyCar challengers.
Ericsson told Viaplay F1 podcast: "My employer, Andretti, has asked me to fly to England to test different simulators. I will provide feedback so they can choose the right model for the whole organisation, including Formula 1, IndyCar, and sports cars.
"Simulators have become an integral part of motorsport, and I’ve been working on improving my own use over the winter. It’s great that they want to use me and my experience to help."